Caffeine and theanine exert opposite effects on attention under emotional arousal

2017 ◽  
Vol 95 (1) ◽  
pp. 93-100 ◽  
Author(s):  
Grace E. Giles ◽  
Caroline R. Mahoney ◽  
Tad T. Brunyé ◽  
Holly A. Taylor ◽  
Robin B. Kanarek
Keyword(s):  
Visual Attention ◽  
Stress Responses ◽  
Repeated Measures ◽  
Emotional Arousal ◽  
Double Blind ◽  
Difference Scores ◽  
Attentional Processes ◽  
Repeated Measures Design ◽  
Film Clips ◽  
The Difference

Tea is perceived as more relaxing than coffee, even though both contain caffeine. L-theanine in tea may account for the difference. Consumed together, caffeine and theanine exert similar cognitive effects to that of caffeine alone, but exert opposite effects on arousal, in that caffeine accentuates and theanine mitigates physiological and felt stress responses. We evaluated whether caffeine and theanine influenced cognition under emotional arousal. Using a double-blind, repeated-measures design, 36 participants received 4 treatments (200 mg caffeine + 0 mg theanine, 0 mg caffeine + 200 mg theanine, 200 mg caffeine + 200 mg theanine, 0 mg caffeine + 0 mg theanine) on separate days. Emotional arousal was induced by highly arousing negative film clips and pictures. Mood, salivary cortisol, and visual attention were evaluated. Caffeine accentuated global processing of visual attention on the hierarchical shape task (p < 0.05), theanine accentuated local processing (p < 0.05), and the combination did not differ from placebo. Caffeine reduced flanker conflict difference scores on the Attention Network Test (p < 0.05), theanine increased difference scores (p < 0.05), and the combination did not differ from placebo. Thus, under emotional arousal, caffeine and theanine exert opposite effects on certain attentional processes, but when consumed together, they counteract the effects of each other.

Unreliability of Difference Scores: A Clarification of the Issues

1977 ◽  
Vol 40 (3) ◽  
pp. 931-935 ◽  
Author(s):  
Stephen Leeb ◽  
Sharon Weinberg
Keyword(s):  
Repeated Measures ◽  
Experimental Situation ◽  
T Test ◽  
Specific Knowledge ◽  
Difference Scores ◽  
Repeated Measures Design ◽  
Power Of The Test ◽  
Mean And Variance ◽  
The Difference ◽  
The Individual

This paper is an attempt to clarify several recent issues that have been raised concerning the unreliability of difference scores. Articles by Overall and Woodward (1975, 1976) and Fleiss (1976) are considered. The conclusions of these articles are shown to be incomplete and to some extent misleading. We begin by noting that within the context of a repeated-measures design, when the reliability of difference scores is other than zero, there exists an interaction of subject by treatment. This interaction will imply the existence of at least one additional systematic variable which contributes to the experimental results. We argue that without specific knowledge about the mean and variance of this systematic variable the interpretation of mean changes across pretest and posttest is ambiguous. With complete knowledge of all variables affecting the experimental situation, the power of the t test on difference scores is directly related to both the individual reliabilities of the separate pretest and posttests and the reliability of the difference scores as long as interaction of subject by treatment is constant across experiments. If, on the other hand, that interaction is not constant across experiments, then the power of the test on difference scores is inversely related to the reliability of the difference scores as long as the individual reliabilities of the pretests and posttests are constant across experiments. Since it is much more reasonable to make the assumption that the interaction is constant across experiments rather than individual test reliabilities, it is more reasonable to conclude that, contrary to Overall and Woodward, power of the t test for difference scores is directly related to the reliability of the difference scores.

Evaluation of the effects of adding vibrotactile feedback to myoelectric prosthesis users on performance and visual attention in a dual-task paradigm

2018 ◽  
Vol 32 (10) ◽  
pp. 1308-1316 ◽  
Author(s):  
Eitan Raveh ◽  
Jason Friedman ◽  
Sigal Portnoy
Keyword(s):  
Visual Attention ◽  
Dual Task ◽  
Repeated Measures ◽  
Gaze Behavior ◽  
Vibrotactile Feedback ◽  
Myoelectric Prosthesis ◽  
Repeated Measures Design ◽  
Performance Time ◽  
Dual Task Paradigm ◽  
Improved Performance

Objective: To evaluate the effects of adding vibrotactile feedback to myoelectric prosthesis users on the performance time and visual attention in a dual-task paradigm. Design: A repeated-measures design with a counterbalanced order of two conditions. Setting: Laboratory setting. Subjects: Transradial amputees using a myoelectric prosthesis with normal or corrected eyesight ( N = 12, median age = 65 ± 13 years). Exclusion criteria were orthopedic or neurologic problems. Interventions: Subjects performed grasping tasks with their prosthesis, while controlling a virtual car on a road with their intact hand. The dual task was performed twice: with and without vibrotactile feedback. Main measures: Performance time of each of the grasping tasks and gaze behavior, measured by the number of times the subjects shifted their gaze toward their hand, the relative time they applied their attention to the screen, and percentage of error in the secondary task. Results: The mean performance time was significantly shorter ( P = 0.024) when using vibrotactile feedback (93.2 ± 9.6 seconds) compared with the performance time measured when vibrotactile feedback was not available (107.8 ± 20.3 seconds). No significant differences were found between the two conditions in the number of times the gaze shifted from the screen to the hand, in the time the subjects applied their attention to the screen, and in the time the virtual car was off-road, as a percentage of the total game time (51.4 ± 15.7 and 50.2 ± 19.5, respectively). Conclusion: Adding vibrotactile feedback improved performance time during grasping in a dual-task paradigm. Prosthesis users may use vibrotactile feedback to perform better during daily tasks, when multiple cognitive demands are present.

scholarly journals Beta alanine supplementation effects on metabolic contribution and swimming performance

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Matheus Silva Norberto ◽  
Ricardo Augusto Barbieri ◽  
Danilo Rodrigues Bertucci ◽  
Ronaldo Bucken Gobbi ◽  
Eduardo Zapaterra Campos ◽  
...  
Keyword(s):  
Repeated Measures ◽  
Energy Demand ◽  
Swimming Performance ◽  
Controlled Study ◽  
Double Blind ◽  
Repeated Measures Anova ◽  
Beta Alanine ◽  
Before And After ◽  
The Difference ◽  
And Performance

Abstract Background Investigations of β-alanine supplementation shows effects on metabolic (aerobic and anaerobic) participation and performance on swimming by a possible blood acidosis buffering. Considering this background, the objective of the present study was to analyze the effects of β-alanine supplementation on metabolic contribution and performance during 400-m swim. Methods Thirteen competitive swimmers underwent a 6-week, double-blind placebo-controlled study, ingesting 4.8 g.day− 1 of β-alanine or placebo. Before and after the supplementation period, the total anaerobic contribution (TAn) and 30-s all-out tethered swimming effort (30TS) were assessed. Anaerobic alactic (AnAl) and lactic energy (AnLa) was assumed as the fast component of excess post-exercise oxygen consumption and net blood lactate accumulation during exercise (∆[La−]), respectively. Aerobic contribution (Aer) was determined by the difference between total energy demand and TAn. In addition to conventional statistical analysis (Repeated measures ANOVA; p > 0.05), a Bayesian repeated measures ANOVA was used to evidence the effect probability (BFincl). Results No differences and effects were found between groups, indicating no supplementation effects. Repeated measures ANOVA, with confirmation of effect, was indicate reduce in ∆Lactate (p: 0.001; BFincl: 25.02); absolute AnLa (p: 0.002; BFincl: 12.61), fatigue index (p > 0.001; BFincl: 63.25) and total anaerobic participation (p: 0.008; BFincl: 4.89). Conclusions Thus, the results demonstrated that all changes presented were evidenced as a result of exposure to the training period and β-alanine supplementation doesn’t affect metabolic contribution and performance during 400-m freestyle.

scholarly journals Ultra-Marathon-Induced Increase in Serum Levels of Vitamin D Metabolites: A Double-Blind Randomized Controlled Trial

Nutrients ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3629 ◽  
Author(s):  
Jan Mieszkowski ◽  
Błażej Stankiewicz ◽  
Andrzej Kochanowicz ◽  
Bartłomiej Niespodziński ◽  
Tomasz Kowalik ◽  
...  
Keyword(s):  
Vitamin D ◽  
Repeated Measures ◽  
Controlled Trial ◽  
Serum Levels ◽  
Vitamin D Metabolites ◽  
Double Blind ◽  
Vitamin D Metabolism ◽  
Repeated Measures Design ◽  
Randomized Controlled ◽  
Type Of Exercise

Purpose: While an increasing number of studies demonstrate the importance of vitamin D for athletic performance, the effects of any type of exercise on vitamin D metabolism are poorly characterized. We aimed to identify the responses of some vitamin D metabolites to ultra-marathon runs. Methods: A repeated-measures design was implemented, in which 27 amateur runners were assigned into two groups: those who received a single dose of vitamin D3 (150,000 IU) 24 h before the start of the marathon (n = 13) and those (n = 14) who received a placebo. Blood samples were collected 24 h before, immediately after, and 24 h after the run. Results: In both groups of runners, serum 25(OH)D3, 24,25(OH)2D3, and 3-epi-25(OH)D3 levels significantly increased by 83%, 63%, and 182% after the ultra-marathon, respectively. The increase was most pronounced in the vitamin D group. Body mass and fat mass significantly decreased after the run in both groups. Conclusions: Ultra-marathon induces the mobilization of vitamin D into the blood. Furthermore, the 24,25(OH)2D3 and 3-epi-25(OH)D3 increases imply that the exercise stimulates vitamin D metabolism.

Cycling Time Trial Performance 4 Hours After Glycogen-Lowering Exercise Is Similarly Enhanced by Recovery Nondairy Chocolate Beverages Versus Chocolate Milk

2016 ◽  
Vol 26 (1) ◽  
pp. 65-70 ◽  
Author(s):  
Adam U. Upshaw ◽  
Tiffany S. Wong ◽  
Arash Bandegan ◽  
Peter W.R. Lemon
Keyword(s):  
Repeated Measures ◽  
Time Trial ◽  
Chocolate Milk ◽  
Double Blind ◽  
Time Trial Performance ◽  
Cycling Time Trial ◽  
Repeated Measures Design ◽  
Dairy Milk ◽  
Cycling Time ◽  
Trial Performance

Postexercise chocolate milk ingestion has been shown to enhance both glycogen resynthesis and subsequent exercise performance. To assess whether nondairy chocolate beverage ingestion post–glycogen-lowering exercise can enhance 20-km cycling time trial performance 4 hr later, eight healthy trained male cyclists (21.8 ± 2.3y, VO2max = 61.2 ± 1.4 ml·kg-1·min-1; M ± SD) completed a series of intense cycling intervals designed to lower muscle glycogen (Jentjens & Jeukendrup, 2003) followed by 4 hr of recovery and a subsequent 20-km cycling time trial. During the first 2 hr of recovery, participants ingested chocolate dairy milk (DAIRYCHOC), chocolate soy beverage (SOYCHOC), chocolate hemp beverage (HEMPCHOC), low-fat dairy milk (MILK), or a low-energy artificially sweetened, flavored beverage (PLACEBO) at 30-min intervals in a double-blind, counterbalanced repeated-measures design. All drinks, except the PLACEBO (247 kJ) were isoenergetic (2,107 kJ), and all chocolate-flavored drinks provided 1-g CHO·kg body mass-1·h-1. Fluid intake across treatments was equalized (2,262 ± 148 ml) by ingesting appropriate quantities of water based on drink intake. The CHO:PRO ratio was 4:1, 1.5:1, 4:1, and 6:1 for DAIRYCHOC, MILK, SOYCHOC, and HEMPCHOC, respectively. One-way analysis of variance with repeated measures showed time trial performance (DAIRYCHOC = 34.58 ± 2.5 min, SOYCHOC = 34.83 ± 2.2 min, HEMPCHOC = 34.88 ± 1.1 min, MILK = 34.47 ± 1.7 min) was enhanced similarly vs PLACEBO (37.85 ± 2.1) for all treatments (p = .019) These data suggest that postexercise macronutrient and total energy intake are more important for same-day 20-km cycling time trial performance after glycogen-lowering exercise than protein type or protein-to-carbohydrate ratio.

scholarly journals Intrinsic Laryngeal Muscle Response to a Public Speech Preparation Stressor

2018 ◽  
Vol 61 (7) ◽  
pp. 1525-1543 ◽  
Author(s):  
Leah B. Helou ◽  
Clark A. Rosen ◽  
Wei Wang ◽  
Katherine Verdolini Abbott
Keyword(s):  
Stress Response ◽  
Stress Responses ◽  
Repeated Measures ◽  
Physiological Stress ◽  
Negative Control ◽  
Laryngeal Muscle ◽  
Repeated Measures Design ◽  
Tibialis Muscle ◽  
Intrinsic Laryngeal Muscle ◽  
Control Activation

Purpose Research suggests that abnormal levels of intrinsic laryngeal muscle (ILM) contraction is a potential causal factor in stress-induced voice disorders. This study seeks to characterize the ILM stress response in a cohort of vocally healthy women. Method The authors used an unblinded, nonrandomized, repeated-measures design. Forty vocally healthy female adults were subjected to a stressful speech preparation task. Measurements of heart rate, blood pressure, trapezius muscle (positive control) activation, and tibialis muscle (negative control) activation were obtained from 37 participants before and during stressor exposure, in a nonvoice and nonspeaking task paradigm, to confirm physiological stress response compared to baseline. Fine wire electromyography of the ILMs (posterior cricoarytenoid, thyroarytenoid/lateral cricoarytenoid muscle complex, and cricothyroid) was performed simultaneously so that the activity of these muscles could be measured prior to and during stressor exposure. Results The protocol successfully elicited the typical and expected physiological stress responses. Findings supported the hypothesis that, in some individuals, the ILMs significantly increase in activity during stress reactions compared to baseline, as do the control muscles. Conclusions This study characterizes ILM responses to psychological stress in vocally healthy participants. Some of the female adults in this study appeared to be “laryngeal stress responders,” as evidenced by increased activity of the ILMs during a silent (i.e., nonvocal, nonspeech) speech preparation task that they considered to be stressful.

Protein kinase B (AKT1) genotype mediates sensitivity to cannabis-induced impairments in psychomotor control

2014 ◽  
Vol 44 (15) ◽  
pp. 3315-3328 ◽  
Author(s):  
S. Bhattacharyya ◽  
C. Iyegbe ◽  
Z. Atakan ◽  
R. Martin-Santos ◽  
J. A. Crippa ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Repeated Measures ◽  
Road Traffic ◽  
Protein Kinase B ◽  
Inferior Frontal Gyrus ◽  
Physiological Effect ◽  
Individual Variability ◽  
Neural Basis ◽  
Double Blind ◽  
Repeated Measures Design

Background.What determines inter-individual variability to impairments in behavioural control that may underlie road-traffic accidents, and impulsive and violent behaviours occurring under the influence of cannabis, the most widely used illicit drug worldwide?Method.Employing a double-blind, repeated-measures design, we investigated the genetic and neural basis of variable sensitivity to cannabis-induced behavioural dyscontrol in healthy occasional cannabis users. Acute oral challenge with placebo or Δ9-tetrahydrocannabinol (THC), the main psychoactive ingredient in cannabis, was combined with functional magnetic resonance imaging, while participants performed a response inhibition task that involved inhibiting a pre-potent motor response. They were genotyped for rs1130233 single nucleotide polymorphisms (SNPs) of the protein kinase B (AKT1) gene.Results.Errors of inhibition were significantly (p = 0.008) increased following administration of THC in carriers of the A allele, but not in G allele homozygotes of theAKT1rs1130233 SNP. The A allele carriers also displayed attenuation of left inferior frontal response with THC evident in the sample as a whole, while there was a modest enhancement of inferior frontal activation in the G homozygotes. There was a direct relationship (r = − 0.327,p = 0.045) between the behavioural effect of THC and its physiological effect in the inferior frontal gyrus, whereAKT1genotype modulated the effect of THC.Conclusions.These results require independent replication and show that differing vulnerability to acute psychomotor impairments induced by cannabis depends on variation in a gene that influences dopamine function, and is mediated through modulation of the effect of cannabis on the inferior frontal cortex, that is rich in dopaminergic innervation and critical for psychomotor control.

Spectral analysis of blood flow oscillations to assess the plantar skin blood flow regulation in response to preconditioning local vibrations

Biorheology ◽  
2021 ◽  
pp. 1-11
Author(s):  
Xiaotong Zhu ◽  
Keying Zhang ◽  
Li He ◽  
Fuyuan Liao ◽  
Yuanchun Ren ◽  
...  
Keyword(s):  
Blood Flow ◽  
Skin Blood Flow ◽  
Repeated Measures ◽  
Underlying Mechanism ◽  
Double Blind ◽  
Blood Flow Oscillations ◽  
Local Vibration ◽  
Repeated Measures Design ◽  
Significant Difference ◽  
Flow Oscillations

BACKGROUND: Local vibration has been shown promise in improving skin blood flow and wound healing. However, the underlying mechanism of local vibration as a preconditioning intervention to alter plantar skin blood flow after walking is unclear. OBJECTIVE: The objective was to use wavelet analysis of skin blood flow oscillations to investigate the effect of preconditioning local vibration on plantar tissues after walking. METHODS: A double-blind, repeated measures design was tested in 10 healthy participants. The protocol included 10-min baseline, 10-min local vibrations (100Hz or sham), 10-min walking, and 10-min recovery periods. Skin blood flow was measured over the first metatarsal head of the right foot during the baseline and recovery periods. Wavelet amplitudes after walking were expressed as the ratio of the wavelet amplitude before walking. RESULTS: The results showed the significant difference in the metabolic (vibration 10.06 ± 1.97, sham 5.78 ± 1.53, p < 0.01) and neurogenic (vibration 7.45 ± 1.54, sham 4.78 ± 1.22, p < 0.01) controls. There were no significant differences in the myogenic, respiratory and cardiac controls between the preconditioning local vibration and sham conditions. CONCLUSIONS: Our results showed that preconditioning local vibration altered the normalization rates of plantar skin blood flow after walking by stimulating the metabolic and neurogenic controls.

Caffeine Supplementation and Reactive Agility in Elite Youth Soccer Players

2014 ◽  
Vol 26 (2) ◽  
pp. 168-176 ◽  
Author(s):  
J. Bradley Jordan ◽  
Ajit Korgaokar ◽  
Richard S. Farley ◽  
John M. Coons ◽  
Jennifer L. Caputo
Keyword(s):  
Repeated Measures ◽  
Perceived Exertion ◽  
Soccer Players ◽  
Ratings Of Perceived Exertion ◽  
Double Blind ◽  
Male Youth ◽  
Warm Up ◽  
Youth Soccer ◽  
Repeated Measures Design ◽  
Reactive Agility

This study examined the effects of caffeine supplementation (6 mg·kg−1) on performance of a reactive agility test (RAT) in 17 elite, male, youth (M = 14 y) soccer players. Using a double-blind, repeated-measures design, players completed 4 days of testing on the RAT after a standardized warm-up. On day 1, anthropometric measurements were taken and players were accommodated to the RAT. On day 2, baseline performance was established. Caffeine or placebo conditions were randomly assigned on day 3 and the condition was reversed on day 4. Players completed 3 randomized trials of the RAT on days 2, 3, and 4 with at least 1 trial to the players’ dominant and nondominant sides. There were no significant differences among conditions in reaction time (RT) to the dominant side, heart rates at any point of measurement, or ratings of perceived exertion (RPE) after completion of the warm-up. Caffeine produced faster RT to the nondominant side (P = .041) and higher RPE at the conclusion of the RAT (P = .013). The effect on the total time (TT) to complete the agility test to the nondominant side approached significance (P = .051). Sprint time and TT to either side did not differ. Caffeine supplementation may provide ergogenic benefit to elite, male, youth soccer players.

Effect of Various Carbohydrate-Electrolyte Fluids on Cycling Performance and Maximal Voluntary Contraction

2010 ◽  
Vol 20 (2) ◽  
pp. 104-114 ◽  
Author(s):  
Matthew S. Ganio ◽  
Jennifer F. Klau ◽  
Elaine C. Lee ◽  
Susan W. Yeargin ◽  
Brendon P. McDermott ◽  
...  
Keyword(s):  
Repeated Measures ◽  
Maximal Voluntary Contraction ◽  
Perceived Exertion ◽  
Cycling Performance ◽  
Voluntary Contraction ◽  
Rating Of Perceived Exertion ◽  
Total Work ◽  
Double Blind ◽  
Repeated Measures Design ◽  
The Central Nervous System

The purpose of this study was to compare the effects of a carbohydrate-electrolyte plus caffeine, carnitine, taurine, and B vitamins solution (CE+) and a carbohydrate-electrolyte-only solution (CE) vs. a placebo solution (PLA) on cycling performance and maximal voluntary contraction (MVC). In a randomized, double-blind, crossover, repeated-measures design, 14 male cyclists (M ± SD age 27 ± 6 yr, VO2max 60.4 ± 6.8 ml · kg−1 · min−1) cycled for 120 min submaximally (alternating 61% ± 5% and 75% ± 5% VO2max) and then completed a 15-min performance trial (PT). Participants ingested CE+, CE, or PLA before (6 ml/kg) and every 15 min during exercise (3 ml/kg). MVC was measured as a single-leg isometric extension (70° knee flexion) before (pre) and after (post) exercise. Rating of perceived exertion (RPE) was measured throughout. Total work accumulated (KJ) during PT was greater (p < .05) in CE+ (233 ± 34) than PLA (205 ± 52) but not in CE (225 ± 39) vs. PLA. MVC (N) declined (p < .001) from pre to post in PLA (988 ± 213 to 851 ± 191) and CE (970 ± 172 to 870 ± 163) but not in CE+ (953 ± 171 to 904 ± 208). At Minutes 60, 90, 105, and 120 RPE was lower in CE+ (14 ± 2, 14 ± 2, 12 ± 1, 15 ± 2) than in PLA (14 ± 2, 15 ± 2, 14 ± 2, 16 ± 2; p < .001). CE+ resulted in greater total work than PLA. CE+, but not PLA or CE, attenuated pre-to-post MVC declines. Performance increases during CE+ may have been influenced by lower RPE and greater preservation of leg strength during exercise in part as a result of the hypothesized effects of CE+ on the central nervous system and skeletal muscle.

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